Gas burner



June 16; 1931. M. J. ossm's GAS BURNER Filed Jan. 2, 1929 2Sheets-Sheet. 2

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Patented June 16, 1931 UNlTED STATES PATENT" OFFICE i g MILLABD J.ROBERTS; OFBUFFALO, NEW YORK, ASSIG-NOR TO ROBERTS-GORDON APPLIANCECORPORATION, OF BUFFALO, NEW YORK GAS BURNER Application filed January2, 1929. Serial No. 329,754.

This invention relates to improvements in gass burners which have beendesigned for use in furnaces, boilers and the like and for either;domestic or industrial purposes.

Oneof its objects is therevision of an automatically controlled gasurner which is eflic ient in operation which is not liable-to get out oforder, which is reliable and positive in action, and which produces amaximum f-uampunt of heat at a minimum expenditure of e Y Another objectof the invention is to so desi the burner that only the proper.proportion of secondaryair is injected for complete combustion," therebpreventing excessive temperature in the c 'mney andmcreasing theeificiency of the combustion.

A further object is to so construct the burner-that a delayed action ofthe secondary air.

' supply is effected when-starting, thereby pro-v ducing a noiselessburner.

Other features of the invention reside in the construction andarrangementof parts hereinafter described and particularly pointed outin the appended claims.

In the accompanying drawings: Figure 1 is a perspective viewof myimproved burner showing the same installed in a round boiler or furnace.Figure 2 is an enlarged vertical section of the diaphragm forcontrolling the secondary air door. Figure 3 is an enlargedtop planview,partly 1n section, of the burner and itsassociated parts taken onl-ine3-3 of Fig. 4. Figure 4: is a 'vertical longitudinal section taken online 4.4, Figure 3. Figure fi is an'enlarged transverse vertical sectionof one of the sections of the burner-body taken on line 55, Fig. 3.Figure 6 is an enlarged detailed-vertical of line 6'-6, Figure'3.

Similar characters indicate corresponding section of the pilot burner,taken in the plane heating apparatus, contains a primary cham-' her forthe receptionv of the gaseous mixture and a secondary chamber forreceiving air to be directed at the base of the gas flame, the secondaryair being delivered through an air duct installed through the ash-pit.door of the boiler and serving as a support on whictrthe burneris-mountcd and also as a housing in which the mixing tubes are arranged.I I do The burnerbody 11 may be of any desired shape and is preferably/made in sections suitably bolted together to facilitate its installationinto the heating apparatus. In its top wall the burner-body has apluralityof outlets or openings 12 for the gaseous mixture and itsinterior is subdivided by a partition 13 into upper and lower chambers14-,-

15, respectively, which preferably extend around the outer side of theburner-body, the latter being provided centrally of its lower side witha depending attaching neck or (:01- lar 16 forming an inlet passage 17for the admission of secondary air. The upper or secondary chamber 14communicates directly with the secondary air passage 17 while the loweror primary chamber 15 is adapted to receive the gaseous mixture, thesecondary air being added to and commingling with the gaseous mixture atthe outlets 12 of the so burner-body. Rising from the partition 13 intothe secondary chamber 14 and opening at their lowerends into theprimarychamber 15 are a pluralityof burner tubesior et's 18, which openat their upper ends at or ad jacent to the burner-outlets 12, wherebythe proper proportion of air in the secondary chamber commingles withthe gaseous. IIllX ture esca ing from the outer ends of the burner tu sto efl'ect-complete combustion of the gas.

The numeral 19 indicates the air duct for delivering the secondary airto the corresponding chamber 14 in the burner-body 11, this ductextending horizontally through the ash-pit opening of the heatingapparatus in the manner shown in Figure 1 and its innerend terminatingin an upright leg orportion 20 to the upper 'end of which the neck 16 ofthe burner-body is fastened, as

shown in Figure 4. ,The ash-pit opening around the duct is bricked up orotherwise sealed and the space between the burnerbody and thesurrounding wall of the heating apparatus is sealed with asbestos orsimilar material. The outer or inlet end of the secondary air duct isexposed to the atmosphere and is controlled by a hinged door 21 which isclosed when the gas supply is turned off.

The gaseous mixture is delivered to the primary chamber 15 of theburner/through the medium of one or more Venturi mixing tubes 22preferably housed within the air duct 19. In the installationillustrated in the drawings, two of such mixing tubes have been shownarranged side by side and connected at their inner ends to tubularfittings 23 )referably cast integral with the burnerbody at oppositesides of its attaching neck 16 and communicating with said primarychamber to effect an equal distribution of the gaseous mixture thereto.The outer ends of the mixing tubes are connected to the main gas supplypipe or manifold 24, which extends transversely through the air duct,gas cocks 25 being provided for regulating the amount of gas deliveredto the burner. The

air supply to these tubes may be regulated by suitable shutters 26.Access to the latter and the gas cooks for regulation may be had throughan opening provided in the top of the air duct 19 and normally closed bya cover plate 27.

Interposed in the gas line 24 is a suitable pressure regulator 28 andarranged between the'latter and the branches leading to the mixing tubes22 is a main gas control valve 29 of any suitable type. In the exampleshown, thisjvalve is of the electrically operated type and is includedin the circuit of a thermostat (not shown), so that when the roomtemperature drops below normal the valve is automatically opened andwhen it reaches a temperature above normal the valve is closed.

An automatic safety pilot burner is employed for lighting the mainburner and its preferred form is shown in Figure 6, where-.

in 30 indicates the base thereof to which its variousparts are attachedand 31 indicates a sheet metal housing surrounding the same and arrangedto be detachably inserted in an opening 32 in the burner-body, as seenin Figures 3 and 4, a spring clip 33 or similar device being used forholding the pilot unit in place in said opening. Rising from the base isa lava burner stem or tube 34 having apertures 35 therein and secured tothe lower end of the base in communication with this tube is a mixer 36which is connected with the gas line. Mounted on the base alongside theburner tube is an expansion element 37 carrying a porcelain pin 38engaging a contact strip 39. fixed at its lower end to a contact screw40. Intermediate its ends this contact strip is adapted to engage asimilar contact screw 41 when the element 37 is expanded, said screwsand contact strip being included in the circuit of the gas control valve29. When the pilot burner is lighted the element 37 expands, closing thecircuit across the contact screws 40, 41 and causing the gas valve 29 tobe turned on in the event that the room temperature is below that atwhich the thermostat is set. Should the room temperature be equal to orabove that point, the'circuit, while established at the contact screws,is broken at the thermostat, as is usual with suchtemperature-controlling devices.

The opening and closing of the door 21 to control the-admission ofsecondary air to the duct 19 and thence to the secondary chamber 14 ofthe burner is preferably accomplished automatically and the mechanism isdesigned to efl'ect a delayed opening of the door when the burner isstarted up so that the secondary air is admitted after the. gas has beenallowed to ignite. To this end a diaphragmhousing or gas chamber 42 ismounted on and in communication with the gas pipe 24 and is disposed onthat side of the air duct opposite to that on which the pressureregulator 28 and the gas control valve 29 are ar ranged, whereby the gasis admitted to the mixing tubes before it reaches said. housing.Disposed centrally in the chamber of the latter is a diaphragm 43 havinga stem 44 extending through the top of the housing and pivotallyconnected to a vertically-swinging lever 45 fulcrumed on a link 46pivoted to the housing, as shown in Figure 1. One end of this leveris'eonne'cted by a chain 47 with the door 21 of the air duct and itsother end has a weight 48 mounted thereon to counterbalance the door. Inits top wall the diaphragm-housing has a vent 49 to effect a gradualdisplacement of air therefrom when the gas is turned on and tocorrespondingly actuate the lever slowly to open the air duct door. Bythis construction, when the gas is first turned on the door 21 isclosed, so that practically pure gas is ignited at the burner;

shortly thereafter this door is automatically opened by the gas pressureto admit air to the duct 19. VVhenthe gas 'is turned off, the door isautomatically closed, producing a. thermos-bottle effect in the heatingapparatus and preventing its cooling down.

Supported in a slightly inclined position around the top of theburner-body 11 and just inwardly of the gas outlets 12 are fire clayradiants 50, which are so designed that they are all equally distantfrom the gas flame and fire-pot Walls. These radiants become red hotsoon after the gas is lighted and hold the heat at the burner andagainst the side walls of the furnace or boiler where it can mostreadily be absorbed. These radiants or refractory members, because oftheir location on the top surface of the burner, heat the top wall ofthe burner both because of heat conducted directly from the radiants tothe top wall, and because of heat radiated from these members to the topwall. The heating of the top wallof the burner results in heating thesecondary air in the chamber 14 of'the burner.

The heating of this secondary air increases materially the efiiciency ofthe burner.

In starting up the burner, the safety pilot is first lighted and as soonas its expansion element 37/ moves the contact strip 39 into engagementwith the contact screw 41, an

electric circuit is closed to automatically effectthe opening of the gasvalve 29 which delivers the fuel to the mixing tubes 22 and thenceintothe primary chamber 15 of the burner where it is ignited at theopenings 12 by the flame issuing from the pilot. At the start the door21 controlling the supply of air to the duct 19 is closed, so thatpractically pure gas is delivered to the burner.

Subsequently, however, the gas pressure acts on the diaphragm 43 toeffect a delayed opening of this door whereupon the air is ad mitted tothe duct to deliver the proper amount of primary air to the mixing tubesand to also direct a supply of secondary air to the burner-chamber 14:where it is injected at the base of the gas flame to produce a highflame temperature and effect complete combustion of the gas. This airduct, which is proportioned to the amount of gas re-.

quired for the burner, acts to control, measureand direct the amount ofair which passes into the burner; it prevents excessive temperature 1nthe chimney; 1t increases the efficiency of production; and the excessof air introduced at the burner-openings is reduced to a minimum. Whenthe room temperature reaches that at which the thermostat is set,thegasvalve 29 is automatically turned off and the diaphragm 43 isallowed tolower, closing the controlling door 21 of the air duct 19.Should the pilot go out, the circuit across the contact screws 40-, 4:1is broken with the result that the gas valve is turned off, therebyeliminating any danger in the use of this improved burner.

I claim as my invention 1. A gas burner, comprising a body having aprimary chamber for the gas, a secondary chamber for the air and outletstherein for the gaseous mixture, burner-tubes communicating. attheir-"lower ends with said primary chamber and discharging at theirupper ends adjacent said outlets, an air duct leading to said secondarychamber, means for interrupting the supply of air to said duct, and amixing tube. for thegaseous mixture and receiving air from within saidair duct and communicating at its inner end with said primary chamber.

2., A gas burner, comprising a body having a primary chamber r'or thegas, a secondary chamber for the air and outlets therein for the gaseousmixture,burner'-tubes communi eating at one end with said primarychamber and discharging at their other ends adjamunicating at its outerend with a source of gas supply and receiving primary air only from saidduct, and conducting the mixture of air and gas to said primary chamber,and means for controlling the admission of air to said duct.

3. A gas burner, comprising a body having a primary chamber for the gas,a secondary chamber for the air and outlets therein for the gaseousmixture, burner-tubes communicating at one end with said primary chamberand discharging at their other ends adjacent said outlets, an air ductleading to said secondary chamber, a mixing tube for the gas and aircommunicating at its outer end with said duct and with a source of gassupply and at its inner end with said primary chamber, and meansgoverned by the How of gas to the mixing tube for controlling theadmission of air to said duct.

4. A gas burner having a primary chamber for a mixture of air andgas, asecondary chamber for supplying secondary air to the flame, an air ductleading to said secondary chamber, a gas supply pipe, a mixing tube toreceive air therefrom and at it's other end into said primary chamber,means for regulating the amount of air delivered to the mixing tube, amovable closure forcontrolling the admission of air to said duct, andmeans governed by the flow of gas to said mixing tube for controllingthe opening and closing of said duct-closure.

5. A gas burner, comprising a body having a primary chamber for amixture of air and gas, a secondary chamber for supplying secondary airto the flame, an air duct'leading to said secondary chamber, a gassupply pipe,

a mixing tube communicating with said duct and with a source of gassupply and receiving primary air only from said duct, and having a.connection to the gas pipe, a movable closure for controlling theadmission of air to said duct, a controlling valve in said gas pipe atone side of its connection with the mixing tube, and means forcontrolling the opening and closing of said duct-closure, said fire-boxof the heating apparatus andcommunicating at its front end with theatmosphere, a burner having outlets therein for a. mixture of gas andprimary air and having a chamber for-admitting secondary air to theflame the latter communicating with the air duct, :1 mixin tube adaptedfor connection tothe gas supp y and openingat its front end into saidair duct to receive primary air from said duct, and at its rear end intoa primary chamber, and means appliedto the front end of the air duct forcontrolling the supply of air thereto.

, 7. A gas burner, comprising av body having a primary chamber andasecondary chamber, an air duct leading to said secondary chamber, a.mixing tubefor the gaseous mixture communicating at its outer end withthe air duct to receiveair therefrom only and at its inner end with"said primary chamber, and

trolling the admission of air thereto, a controlling valve in saidgaspipe, and means for controlling the opening and closing of saidduct-closure, said means including a diaphragm actuated by the pressurein the gas pipe, and connections between the diaphragm and said closurewhereby a delayed opening of the latter is effected when the gascontrolling valve is opened.

MILLARD J. ROBERTS.

means for controlling the passage of air to said duct.

. 8. A gas burner, comprising a body having superposed primary andsecondary chambers for receiving the gaseous mixture and secondary air,respectively, an air duct leading to said secondary chamber, and amixing tube for the gaseous mixture communicating at its outlet end withsaid primary chamber and at its inlet end with said air duct to receiveprimary air therefrom, and means for controlling the passage of air tosaid duct.

9. A gas burner, comprising a body having a primary chamber and asecondary chamber,

an air duct leading to said secondary chamber, I. gas supply pipe, amixing tube in communication at one end with said gas supply pipe andthe atmosphere and at its other end with said primary chamber, a movableclosure applied to said air duct for controlling the admission of airthereto, automatic means for operating said closure, and means forgovernmg said automatic means to effect a delayed opening of said airduct closure.

10. gas burner, comprising a body having a primary chamber and asecondary chamr, an air duct leading to said secondary chamber, a gassupply pipe a mixing tube in communication atone end with said gassupplypipe and the atmosphere and at its other end with said primary chamber,a movable closure ap lied to said air duct for controlling the amimion'of air thereto, and actuating means for said closure, said meansbeing 'in communication with the gas pipe an governed by thepressure-therein for effecting a delayed opening action of said closure.11. A gas burner, comprising a body hav-

